An electrical lead suspension (henceforth referred to as ELS), used in a Data Access Storage Device (DASD), e.g., a hard disk drive (HDD), comprises flexing interconnect that is typically formed of a laminate comprised of at least three layers of material. These laminate layers may include a signal-conductor layer from which signal traces are formed, a dielectric layer, e.g., polyimide, for insulation and support for the signal-conductor layer, and a conductive base-metal layer to provide support for the dielectric layer. The flexing interconnect spans a hinge area of the ELS where a load beam attaches to a mount plate. An ELS may be formed by a subtractive process, such as, e.g. an Integrated Lead Suspension (ILS), an additive process, such as, e.g., a Circuit Integrated suspension (CIS) or as a Flex-On Suspension (FOS) when the FOS is attached to a base metal layer, or it may be a Flex Gimbal Suspension Assembly (FGSA) that is attached to a base metal layer, or any form of lead suspension used in a DASD.
Prior Art FIG. 1 is a top plan view 100 of a portion of a flexing interconnect having write traces 120 and read traces 130, formed of the signal-conductor layer of a laminate and supported by dielectric layer 140 and a single serpentine pattern 110, formed of the base-metal layer of the laminate, according to an embodiment of the conventional art. In order to provide flexibility in the hinge area of the laminate, the supporting base-metal layer is, according to conventional art, in the form of serpentine pattern 110. In other words, portions of the base-metal layer are removed so as to allow for flexibility in the hinge area to allow the head to fly properly, while providing a necessary amount of mechanical stiffness for supporting the signal traces 120 and 130 that are the read and write traces.
While the serpentine pattern 110 can provide the appropriate mechanical stiffness, the connecting serpentine pattern underneath the write and read traces 120 and 130 results in write-to-read crosstalk that degrades the performance of the read sensor. A large write driver voltage produces a large current in the write traces 120, in turn, write current induces currents in read traces 130 through serpentine base-metal layer 110 resulting in crosstalk between write and read traces. The read traces 130 connect to a very voltage-sensitive read sensor.